Kasmere Lake NTS
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Manitoba Geological Survey B.G.C.M. Series Kasmere Lake, NTS 64N, 1:250 000 MARGINAL NOTES LEGEND The Kasmere Lake map area (NTS 64N) lies on the south and east flanks of the Hearne Province, part of the The Wollaston Domain and Seal River Domain share a common lithostratigraphy and metamorphic history. MUDJATIK DOMAIN SEAL RIVER DOMAIN Archean Rae-Hearne craton. The Snowbird Shear Zone divides the Rae-Hearne craton into the Rae Province Wollaston Group paragneiss unconformably overlies Archean granitoid rocks and possibly Archean volcanic Proterozoic Proterozoic to the west and the Hearne Province to the east (Hoffman, 1990). The Archean continental crust of the Hearne and sedimentary-derived gneiss. The Wollaston Domain is a northeast-trending fold belt with minor Hudsonian O O 0 102 O 100 0 0 0 Province is overlain by Paleoproterozoic cover rocks and, together with the cover rocks, has undergone varying plutonism, whereas the Seal River Domain exhibits an early, easterly trending, open fold set locally overprinted 30’ 0 30’ Hudsonian Hudsonian 350000 101 degrees of thermotectonism during the Paleoproterozoic Trans-Hudson orogeny (Cree Lake Ensialic Mobile by northeasterly structures. The Seal River Domain contains a greater volume of Hudsonian plutons. O 400000 Nunavut O Granite; Gf - pink granite, fluorite bearing; Gj - granite and 0 60 60 0 Granite, massive to foliated, aplite pegmatite; Gp - pink 66 granodiorite diatexite to biotite-metatexite garnet; Zone; Lewry et al., 1978; Lewry and Sibbald, 1980). Parts of the Hearne Province are considered to be H G G Gf W HW 50 porphyritic granite cratonic or semicratonic with respect to the Trans-Hudson Orogen, since they are little affected by Hudsonian The Wollaston Domain is defined by 1) the predominance of supracrustal-derived gneisses of the Wollaston Gw Manitoba Gw - granite and Hurwitz Group metagreywacke, Tk R G 000 thermotectonism. One of these regions, the Ennadai Block (Lewry et al., 1985), trends southwesterly from Group, and 2) the fold-belt structural style. These criteria were first established in Saskatchewan and termed HP P u t a h o w metasiltstone Tn Gj Rankin Inlet to the extreme northwest corner of Manitoba. The Hearne Province is separated from the accreted the Wollaston Fold Belt System (Money, 1965) with a width of approximately 100 km. The Wollaston Domain G Gh Hybrid granite Paleoproterozoic juvenile terranes of the Trans-Hudson Orogen to the south by the Wathaman-Chipewyan in Manitoba is well defined from the Manitoba-Saskatchewan border, where it is approximately 90 km wide Tn Gj T Gh Granite with grey tonalitic to granodioritic gneiss L i t t l e WSk (Whiskey Jack Lake map area, NTS 64K) and trends northeasterly to the south end of Kasmere Lake, where it 000 batholithic domain, which is interpreted as the root of a magmatic arc. HDo T 50 WN Tonalite, cordierite bearing, tourmaline; Tn - tonalite with is approximately 35 km wide (Kasmere Lake map area, NTS 64N). Northeast of Kasmere Lake, the Wollaston HW W 66 Tk WNh Nh T The Ensialic Mobile Zone has been subdivided into six domains in Saskatchewan and Manitoba. They are the Domain is less well defined and narrows to 20 km at the Nunavut border. The Manitoba segment of the G WNk R Quartz feldspar porphyry semipelitic paragneiss to metatexite Mudjatik, Peter Lake (Saskatchewan only), Wollaston, Seal River, Great Island and Nejanilini domains. The Wollaston Domain is characterized by tightly spaced elongate domes, antiforms and synforms that are WNh T T Mudjatik and Wollaston domains and the west end of the Seal River Domain occur in the Kasmere Lake map generally tight to isoclinal. The antiforms contain cores of pelitic and semipelitic gneiss (unit WN) and the WN Wollaston Group HW area (NTS 64N). Tk Tonalite, cordierite bearing tourmaline Meta-arkose; derived arkosic gneiss with metatexite; elongate domes are cored by Archean hypersthene-bearing enderbite to monzocharnockite (unit Zx). The G WSb T T synforms contain in their cores Wollaston Group meta-arkose (unit WSn) or biotite psammite gneiss (unit G Putahow WSn WSb - biotite psammite gneiss, calc-silicate lenses; WSk WSb). WSk - with albite-pyroxene rocks Lithostratigraphy HP Hurwitz Group WNh WNn Metasedimentary rocks of the Paleoproterozoic Hurwitz Group and sedimentary-derived gneissic rocks of the The Seal River Domain occurs east of the Wollaston Domain. It is characterized by large, east to east- WKb Calc-silicate rocks with biotite psammite gneiss Lake Tf HDo Dolomite Wollaston Group unconformably overlie the Archean basement rocks of the Hearne Province. The rocks of the southeast trending folds and faults that have been further deformed by discrete northerly and northeasterly WNh Hurwitz Group occur almost entirely in Nunavut as discontinuous structural keels along a southeasterly trend trending structures. Based on magnetic trends and attitudes of metamorphic layering, the western boundary of Gh WNn Semipelitic paragneiss to metatexite, muscovite cordierite P a r t r i d g e R i v e r NUELTIN LAKE from Rankin Inlet to the northwest corner of Manitoba. the Seal River Domain is irregular and step-like, reflecting a pattern of structural interference. WN garnet sillimanite andalusite hypersthene; W HP Argillite WNj - semipelitic paragneiss to metatexite, + garnet with Tk Tk Kb The west end of the Seal River Domain, for a distance of approximately 40 km to the east, is divided into two Tk WNh granodiorite diatexite to biotite metatexite; WNn - with Hurwitz Group WN WSb segments by the Hudsonian Topp Lake pluton, a large, Paleoproterozoic, synkinematic, porphyritic G tonalite monzogranite intrusion (unit Gp) that occupies the southeast quarter of the Kasmere Lake map area. Tice HW Metagreywacke, metasiltstone Rocks of the Hurwitz Group are present in the northwest corner of the Kasmere Lake map area, based on Tk WN WNn WQ Impure quartzite to quartzite mapping and interpretation by Weber et al. (1975a). Argillite (unit HP) overlain by dolomite (unit HDo) occurs in WNh Southwest of the Topp Lake pluton, the structure is characterized by basin-and-dome polyphase deformation. WSk WNh WNn the Ennadai Block in the extreme northwest of the Kasmere area. The argillite has been correlated with the Wollaston Group This fold pattern is the result of interference of the northeasterly Wollaston fold trend and the easterly Seal Lake T T Ameto Formation of the Hurwitz Group in Nunavut (Weber et al., 1975a) and a metagreywacke, with WNn WSn River fold trend. Major structures are outlined by large-scale layering of supracrustal-derived paragneiss and Biotite psammite gneiss, calc-silicate lenses; WSk - with Proterozoic and/or Archean metasiltstone (unit HW) and minor calc-silicate zones, occurring in the Wollaston Domain from Tice Lake G WSb migmatite. Domes are cored by Archean and/or Hudsonian granitic rocks. The basins are cored by arkosic G albite-pyroxene rocks northeasterly through the area of Putahow Lake into Nunavut. This unit (HW) has been tentatively correlated Foliated alaskite with hybrid granite and pink aplite, gneiss and/or calc-silicate rocks. Synforms in general are highly tightened and the trends of axial traces are G Gk with a similar greywacke of the Hurwitz Group in the Ennadai Lake area (Nunavut). Eade (1971) considered highly variable. This basin-and-dome pattern continues to the southwest into the Whiskey Jack Lake map area WSn Nahili hornblende; Gn - foliated granite the greywacke to be part of the Ameto Formation and possibly time equivalent to the argillite. (NTS 64K). W WK T WK Calc-silicate rocks HDo Sb WN HP G G Granodiorite diatexite to biotite metatexite, garnet Wollaston Group An easterly trending, approximately 40 km wide synform cored by semi-pelitic to pelitic gneiss and intruded by T WNn variably magnetic pink monzogranite, lies on the north flank of the Topp Lake pluton. The south limb of the WK Albite-pyroxene rocks T WSk WK The basal unit of the Wollaston Group in Manitoba and Saskatchewan is a psammitic to semipelitic garnet- synform comprises magnetiferous arkosic gneiss, calc-silicate and biotite psammite gneiss (unit WSb). The Gf WK WNn WSn 0 Tn 0 Archean biotite ± cordierite gneiss (unit WN). It contains sporadic interlayers of calc-silicate rocks and impure to pure north limb of the synform comprises magnetiferous arkosic gneiss, and calc-silicate metasedimentary rocks 45’ R i v e r WSb WQ 45’ Koona Semipelitic paragneiss to metatexite, + garnet; WNn - with quartzite. The gneiss shows a well developed metamorphic layering defined by alternating grey to dark grey, intruded by pyrrhotite-bearing amphibolite after gabbro (Peck et al., 1994). The highly varied magnetic WN tonalite; WNh - with biotite psammite gneiss; WNk - with lits Lake Zx Hypersthene granite (monzocharnokite) biotite-rich layers (1-100 cm thick), and white to cream, medium- to coarse-grained granitic . Both of these signature of the semi-pelitic to pelitic gneiss in the core of the synform is anomalous; regionally, the paragneiss WSn WSb Lake calc-silicate and biotite psammite gneiss HDo WN WK components are intruded by white, pegmatitic, boudinaged sills of granite. Areas underlain by these rocks has a characteristically low magnetic intensity. The magnetic data suggest that the paragneiss may form a thin Tk G WSb Tn coincide with areas of low magnetic intensity (2000-2200 gammas). cover overlying magnetiferous arkosic gneiss. The presence of the basal semi-pelitic to pelitic gneiss in the G G WNn Proterozoic and/or Archean core of the synform overlying younger arkosic gneiss, the uppermost unit of the Wollaston Group, is evidence Tn WK WNn Garnet and cordierite are common accessory minerals in the garnet-biotite gneiss; sillimanite is a minor T of a structural inversion. WNn Granodiorite diatexite to biotite metatexite, garnet component and occurrences of hypersthene and andalusite are more localized (Schledewitz, 1986).